curs_kernel(3x) — Linux manual page


curs_kernel(3X)                                          curs_kernel(3X)

NAME         top

       def_prog_mode, def_shell_mode, reset_prog_mode, reset_shell_mode,
       resetty, savetty, getsyx, setsyx, ripoffline, curs_set, napms -
       low-level curses routines

SYNOPSIS         top

       #include <curses.h>

       int def_prog_mode(void);
       int def_shell_mode(void);

       int reset_prog_mode(void);
       int reset_shell_mode(void);

       int resetty(void);
       int savetty(void);

       void getsyx(int y, int x);
       void setsyx(int y, int x);

       int ripoffline(int line, int (*init)(WINDOW *, int));
       int curs_set(int visibility);
       int napms(int ms);

DESCRIPTION         top

       The following routines give low-level access to various curses
       capabilities.  These routines typically are used inside library

   def_prog_mode, def_shell_mode
       The def_prog_mode and def_shell_mode routines save the current
       terminal modes as the “program” (in curses) or “shell” (not in
       curses) state for use by the reset_prog_mode and reset_shell_mode
       routines.  This is done automatically by initscr.  There is one
       such save area for each screen context allocated by newterm.

   reset_prog_mode, reset_shell_mode
       The reset_prog_mode and reset_shell_mode routines restore the
       terminal to “program” (in curses) or “shell” (out of curses)
       state.  These are done automatically by endwin(3X) and, after an
       endwin, by doupdate, so they normally are not called.

   resetty, savetty
       The resetty and savetty routines save and restore the state of
       the terminal modes.  savetty saves the current state in a buffer
       and resetty restores the state to what it was at the last call to

       The getsyx routine returns the current coordinates of the virtual
       screen cursor in y and x.  If leaveok is currently TRUE, then
       -1,-1 is returned.  If lines have been removed from the top of
       the screen, using ripoffline, y and x include these lines;
       therefore, y and x should be used only as arguments for setsyx.

       Few applications will use this feature, most use getyx instead.

       The setsyx routine sets the virtual screen cursor to y, x.  If y
       and x are both -1, then leaveok is set.  The two routines getsyx
       and setsyx are designed to be used by a library routine, which
       manipulates curses windows but does not want to change the
       current position of the program's cursor.  The library routine
       would call getsyx at the beginning, do its manipulation of its
       own windows, do a wnoutrefresh on its windows, call setsyx, and
       then call doupdate.

       Few applications will use this feature, most use wmove instead.

       The ripoffline routine provides access to the same facility that
       slk_init [see curs_slk(3X)] uses to reduce the size of the
       screen.  ripoffline must be called before initscr or newterm is
       called, to prepare these initial actions:

       •   If line is positive, a line is removed from the top of

       •   if line is negative, a line is removed from the bottom.

       When the resulting initialization is done inside initscr, the
       routine init (supplied by the user) is called with two arguments:

       •   a window pointer to the one-line window that has been
           allocated and

       •   an integer with the number of columns in the window.

       Inside this initialization routine, the integer variables LINES
       and COLS (defined in <curses.h>) are not guaranteed to be
       accurate and wrefresh or doupdate must not be called.  It is
       allowable to call wnoutrefresh during the initialization routine.

       ripoffline can be called up to five times before calling initscr
       or newterm.

       The curs_set routine sets the cursor state to invisible, normal,
       or very visible for visibility equal to 0, 1, or 2 respectively.
       If the terminal supports the visibility requested, the previous
       cursor state is returned; otherwise, ERR is returned.

       The napms routine is used to sleep for ms milliseconds.

RETURN VALUE         top

       Except for curs_set, these routines always return OK.

       curs_set returns the previous cursor state, or ERR if the
       requested visibility is not supported.

       X/Open defines no error conditions.  In this implementation

       def_prog_mode, def_shell_mode, reset_prog_mode, reset_shell_mode
            return an error if the terminal was not initialized, or if
            the I/O call to obtain the terminal settings fails.

            returns an error if the maximum number of ripped-off lines
            exceeds the maximum (NRIPS = 5).

NOTES         top

       Note that getsyx is a macro, so & is not necessary before the
       variables y and x.

       Older SVr4 man pages warn that the return value of curs_set “is
       currently incorrect”.  This implementation gets it right, but it
       may be unwise to count on the correctness of the return value
       anywhere else.

       Both ncurses and SVr4 will call curs_set in endwin if curs_set
       has been called to make the cursor other than normal, i.e.,
       either invisible or very visible.  There is no way for ncurses to
       determine the initial cursor state to restore that.

PORTABILITY         top

       The virtual screen functions setsyx and getsyx are not described
       in the XSI Curses standard, Issue 4.  All other functions are as
       described in XSI Curses.

       The SVr4 documentation describes setsyx and getsyx as having
       return type int.  This is misleading, as they are macros with no
       documented semantics for the return value.

SEE ALSO         top

       curses(3X), curs_initscr(3X), curs_outopts(3X), curs_refresh(3X),
       curs_scr_dump(3X), curs_slk(3X), curs_variables(3X).

COLOPHON         top

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